Alarmist messages about global warming are counter-productive, the head of a leading climate research centre says.

Professor Mike Hulme, of the UK's Tyndall Centre, has been conducting research on people's attitudes to media portrayals of a catastrophic future.

He says strong messages designed to prompt people to change behaviour only seem to generate apathy.

His initial findings will be shown to a meeting run by the British Association for the Advancement of Science.

"There has been over-claiming or exaggeration, or at the very least casual use of language by scientists, some of whom are quite prominent," Professor Hulme told BBC News.

His concern is that these exaggerations have given the green light to the media to use the language of fear, terror and disaster when covering scientific reports - even when those reports are much more constrained in their description of the course of likely future events.

He says extravagated claims simply generate a feeling of helplessness in the public.

"My argument is about the dangers of science over-claiming its knowledge about the future and in particular presenting tentative predictions about climate change using words of 'disaster', 'apocalypse' and 'catastrophe'," he said.

'Poor presentation'

The study compared the responses of a group of people shown sensational media coverage with those given the more sober information from scientific reports.

The initial findings suggest that those shown doom-laden messages tended to believe the problem could come to a head further into the future. This group also felt there was little they could do to affect the planet's future.

"Not only is this not a good way of presenting climate change science, but even in trying to effect change, it's self-defeating," Professor Hulme said.